Unidirectional tape is commonly understood to be a thin strip or band of continuous unidirectional fibres (for instance glass fibres, carbon fibres, or other known reinforcing fibres) impregnated with a polymer resin. The tape may typically have a width in the order of magnitude of 1 to 15 cm wide, perhaps wider, and a thickness of less than 1 mm, such that the tape may be provided on a reel.
In a conventional process, it is known to form a composite article with a loop-shaped fibre reinforcement by winding unidirectional fibre reinforced tape around a shape-forming element, the tape being heated as it is wound to soften the polymer resin such that the layers of tape bind together and follow the contour of the shape-forming element. The heating and subsequent cooling process is time-consuming and occupies the tape winding and forming machine, thus resulting in a costly manufacturing process.
It is also known to form articles with fibre-reinforced polymer resins provided in sheets or wound tape by cutting sections of tape and two-dimensional shaped blanks out of sheets and stacking them together in a cold state as described in U.S. Pat. No. 5,394,773. The stacked sheets are then placed in a die and subsequently subjected to heat and pressure to soften and bind the polymer resin of the stacked sheets and layers together. One of the drawbacks of the latter process is the difficulty of properly holding and positioning the assembled layers together, especially when transporting the assembly from one manufacturing station to another. Also, for articles that are intended to support high tensile (traction) or bending forces, conventional cold UD tape stacking and forming processes are not well adapted to form complex shapes with optimal tensile resistance properties, as compared to the hot forming process described above.